1. Field
The present invention relates to an image forming apparatus having a cooling device and a method of controlling the image forming apparatus.
2. Description of the Related Art
An image forming apparatus, such as a copying machine and a printer, is often provided with a cooling device, such as a cooling fan, to cool the control unit such as CPU in the apparatus. In the event of the occurrence of an abnormality in the cooling device, the CPU (control unit) is heated above the tolerance, which possibly gives damages to the CPU itself or the peripheral components or causes them to malfunction. Under these circumstances, there have been made proposals for various techniques to address an abnormality in the cooling device of this kind.
An image forming apparatus disclosed in JP-A-2005-148669 includes cooling device driving means furnished with not only the capability of driving the cooling fan, but also the capability of outputting an abnormal rotation signal of the fan to the CPU. Upon receipt of the abnormal rotation signal of the cooling fan, the control unit determines whether the cooling fan is operating normally by turning ON and OFF the power supply of the cooling fan repetitively several times. When determined as not being normal, the control unit notifies the user of the presence of an abnormality in operations of the cooling fan through the operation panel and stops the cooling fan, after which it stops the image forming operation.
An information processing apparatus disclosed in JP-A-11-134220 includes abnormality detecting means for detecting an abnormality in the cooling fan, abnormality detection signal transmitting means for transmitting an abnormality detection signal on the basis of the detection of an abnormality, and warning means for sending a warning upon receipt of the abnormality detection signal. In the event of the detection of an abnormality, the user is informed of the presence of an abnormality in operations of the cooling fan by sounding a warning and lighting ON the pilot lamp or by displaying a warning message on the operation panel having an independent power supply system by the warning means, while power supply to the apparatus is stopped except for the operation panel.
The CPU self-heats even in an idle state. Hence, it is impossible to prevent an overheating of the CPU resulting from the self-heating with a technique of subjecting the CPU to natural cooling by stopping the image forming operation like the technique disclosed in JP-A-2005-148669.
There is a case where an error, such as paper jamming, is occurring in a printer of the image forming apparatus during the occurrence of an abnormality in the cooling fan. In this case, with a technique of automatically turning OFF the power supply of the image forming apparatus at the occurrence of an abnormality in the cooling fan like the technique disclosed in JP-A-11-134220, it is impossible to notify the user of an error, such as paper jamming, that occurred during the occurrence of an abnormality in the cooling fan, because the power supply of the image forming apparatus is stopped. Hence, in a case where paper jamming had occurred, a sheet of paper is left in the image forming apparatus. This sheet of paper and toner particles fixed thereon may firmly adhere to the interior of the image forming apparatus. Such adhering materials may cause a failure of the image forming apparatus, which shortens the life of the image forming apparatus.